Burner control system



Nov. 29,A 1938. V c. G, KRONMILLER 2,138,792

BURNER CONTROL SYSTEM Filed July 5, 1936 4 SheeKZS-Sheekl l Nov. 29, 1938.

C. G. KRONMILLER BURNER CONTROL SYSTEM Filed July s, 1956 Y 4 sheets-sheet 2 gri/WMM NOV- 29, 1938- c. G. KRONMILLER BURNER CONTROL SYSTEM Filed July 3, 1936 4 Sheets-Sheet 3 Nov. 29, 1938. c. G. KRONMILLER 2,138,792

BURNER CONTROL SYSTEM Filed Julyv, 1955 4 SheeS-Sheel '4' Patented Nov. 29, 1938 1 comen svs'rnrn Carl G. Kronmiller, Minneapolis, assignor to Minneapolis-Honeywell Retor Cammy, Y minneapolis, Minn., a corporation of Delaware I AApplication .l 3, 1936, Serial No. 88,781

il@ :maar

- My inventionrelates to a burner control system and more pmcularly to control apparatusV for use in connection with iiuid fuel burners.

The invention is cularly concerned with a 5 new and novel uid fuel controlling means which is designed Vto control the ovv of duid fuel to both a fuel 'burner and to a pilot burner and at the same time to regulate the ssion of air to said burners. l@ One ci the objects of the present invention is to provide for use in a duid fuel burner control system a duid ow controlling device and a novel operating means therefor which is particularly v adapted to operatelsaid duid now controlling de- Y vice slowly. from closed to open msition to avoid toorapid admission of fuel to the burner.

r A 'further object of the invention is to provide in a burner control system a. valve in control of 'the ow of fuel to the burner, a second valve in a2@ control ofthe ow of fuel to the pilot burner, and

an air damper for controlling the admission of air to the burners, all of which are operated in a deiinite sequence by -a single motor means.

A further' object of the present invention is to provide a burner control system having a main burner and a pilot burner with a main' valve and a pilot valve.' respectively, controlling said burners in which a motor is provided for operating the two valves, which motor is connected to the main valve through a lost motion connection and in which the pilot valve is actuated by the motor while taking up the lost motion between the motor and the main valve.

A further object of the present invention is to provide a. new and novel electrically operated motorized uid now control member' wherein the motor is provided with two eld windings of different strength and wherein a new andv novel method is employed for controlling the energization of these eld windings through a thermo` static or other control switcli and through a further switching apparatus operated by thel motor.

A further object of the present invention is to provide in a motorized valve a double valve disk construction wherein a smaller valve` disk is moved from its s'eat iirst and relieves the uid pressure on the larger ofy the two valve disks.l

A further object of the present invention is to provide a new and novel arrangement in a mechanism having a movable element biased in one direction by a spring and operated in a different direction by a motor in which a shaft is employed to transmit the motion imparted by the motor or spring to the element to be moved and in ."5 which .a novel means is employed toprevent-the thrust arising by the opposed actions of the spring and motor from being transmitted to said shaft. l

A further object of the present invention is to provide. a motorized valve of the type wherein a 5 valve is moved to one position by a spring and to .a diierent position by a motor in OpDOSition to the spring in which means is provided for adjusting the travel ofthe valve without varying the amount of compression of the spring necessary l0 to eect such travel.

Further objects of this invention will be apparent from the accompanying specification, claims and drawings, of which:

Figure 1 is an elevational view,A partly in sec- 15 y tion, of my improved valve;

Figure 2 is a view o a portion of the operating mechanism of my valve taken in the opposite direction from Figure l;

Figure 3 is a section takenalong the line v3--3 20v of Figure l;

Figure 4 is an elevational view of the motor mechanism looking in the direction of the arrows adjacent line i-li of Figure 1 and with the motor housing in section along said line;

Figure 5 is a plan view of the motor mechanism with the covering of the housing removed;

' Figure 6 is a section along the line 6-4-6 of Figure 5;

Figure 'Z is a sectional view along line 'l-l' of 30 Figure 5; p

Figure 8 is a detailed View of a portion of the operating mechanism with a portion thereof in section along line of Figure 1;

Figure 9 is a view of the pilot valve operating 35 mechanism with a portion thereofl in section;

Figure l0 is alietailed, view in section taken along line lll-lil of Figure 1;

Figurell is an end view of the motor mecha,- -nism showing particularly the manual latching 40 mechanism associated therewith;

Figure 12 is `a view of the manual latching mechanism viewed from the opposite direction from which Figure l1 is viewed y 45 Figure 13 is a schematic view of a new and novel burner control system employing my improved valve; ,f

Figure 14 is a view of a. portion of the lever mechanism of a modification of my preferred 50 species;

Figure 15 is a sectional view taken along the linel5-l5 ofFigllre 14; C

, Figure 16 ls a. view of a modified form of pilot lvalve and the operating mechanism thereof;

Figure 1'7 is a view taken in section along the line I1-I1 of Figure 16, and

Figure 18 is a sectional view taken along the Referring to` Figure 1 of the drawings, the valve body proper is designated by the reference numeral I0. The valve body is provided with the usual inlet- II and outlet I2. Extending across the interior of the valve body is a transverse partition wall 9 which is provided with an opening therein to furnish a valve seat I3. A main valve disk I4 is adapted to seat on the valve seat I3. Mounted in said valve disk is an annular member I5 of suitable valve facing material. The valve disk is further provided with a downwardly extending, threaded, tubular extension I6 and threaded onto this extension is a valve guide member I1. The valve guide member comprises a body portion I8 which is provided with a plurality of apertures I9 to permit passage of fluid therethrough, The guide I1 is further provided with elongated spaced guide -members 20.

The upper portion of valve disk I5 is provided with a raised annular portion 22 forming a seat upon which a, second valve'disk 23 is adapted'to seat. This valve disk is likewise provided with an annular member 24 of suitable valve facing material. The valve disk 23 is further provided with a screw threaded downwardly extending` portion 25 on the exterior of which is threaded a guide member 26. This guide member is adapted to guide the movement of valve disk 23 by engaging the walls of the aperture 29 of valve disk I4. A cap screw 30 is also threaded into the downwardly extending portion 25 of valve disk 23 and the head of this screw serves to limit movement of valve disk 23 away from valve disk I4. On the upper portion of valve disk 23 an upstanding curved flanged -member 32 is provided. This member is open at one side so as to slidably receive a stem 34 which is provided with a head portion 36 adapted to engage under the flange of member 32.

Stem 34 is provided at its upper end with two spaced annular collars 48 and 4I. As more clearly shown in Figure 2, these two collars, 40 .and 4I, receive between them inwardly extending pins 43 of a lever 44 having a bifurcated portion 45, in the legs of which, the pins 43 are secured. As shown more clearly in -Ftgure 3, lever 44 'is secured to a shaft 41 through a hexagonal portion 48 on said shaft which is adapted to extend through a similar hexagonal opening in an enlarged head 49 of lever 44. It will be seen that rotation of shaft 41 causes a resulting -rotation of lever 44 which in turn causes movement of valve stem 34. When this rotation of shaft 41 is in a direction to cause upward movement of valve stem 34, the valve disk 23 will first be raised until the head of cap screw 38 engagesthe lower portion of extension I6 of valve disk I'4,.where upon further movement of valve stem 34 is eective to lift the main valve disk I4 0E of its seat. In view of the fact that valve disk I4 has a central aperture 29 vtherethrough which communicates with apertures I9 in the valve guide member I1, a movement offv'alve disk 23 away from seat 22 permits the fluid pressure Von top of valve disk I4 to be -relieved so that the large This adapter member may be of any type which permits a standard valve head member to be attached to various sizes of valve bodies. As'shown most clearly in Figures 2 and 3, the valve cap 58 is provided with a plurality of upstanding studs 53 which serve to support a base plate 54 on which the motor mechanism 55 is mounted. Base plate 54 is secured to studs 53 through any suitable fastening means, such as machine screws 56 attached to the underside of valve cap 50. In the interior thereof is a valve guide member 58 which member serves to guide valve stem 34.

A means for sealing shaft 41 is shown most clearly in Figure 3. Extending into opposite` an enlarged annular shoulder in which is mounted an annular member 63 of packing material. This packing material 63 is adapted to be engaged by a shoulder 64 on shaft 41. In-the outermost portion of sleeve member 59 is a spring 66 which bears against a movable pin 61 which in turn is in abutting engagement with shaft 41. The action of spring 66 is accordingly to move shaft 41 to the right and to urge shoulder 64 into engagement with packing material 63, thus serving to seal the shaft against the escape of fluid. As a further sealing Arneans, sleeve 69 is provided at its outer end with an internal annular recess filled with packing 69 which is held in position by a gland nut 10. Inasmuch as escape of fluid from the interior of valve cap 50 adjacent sleeve members 59 and 68 is prevented by reason of the threaded connection and packing washers 1I and 12 which are clamped between the sleevemembers andthe valve cap and by reason of the sealing means Just described comprising shoulder 64 and packing 63, shaft 41 is eectively sealed. against the escape of fluid while at the same time free rotation of the shaft is permitted.

The means for transmitting rotation to the shaft 41 will now be described. It will be noted from Figures l and 2 that the outermost end of shaft 41 is provided with asquare end. Mounted on this square end is a lever 15 which may be of any desired construction. As best shown in Figure 10, this lever has a reversely bent portion 16 to provide two spaced arms 11 and 18 which en-` gage the shaft at spaced points. The reversely bent portion 16 is provided with a slot 13 as best shown in Figure 1, and extending between arms 11 and 18 is a bolt 19 which upon being tightened serves to clamp lever 15 securely to shaft 41. Lever 16 is connected at its outer end to a bell crank lever 4|36 through a cap screw 81. Bell crank lever 86 is provided with a hub portion 8: which is mounted upon a bearing constituted by the outer annular extension 89 of sleeve member 60. Pivotally connected to one arm 90 -of the bell crank lever 86 is a rod 9I. This rod 9! extends into a spring housing 92 and is' provided at its outermost end with a collar member 93 which is engaged by a spring 94. Collar member 93 is held inlposition-on rod 9| by a nut 95 which can beemployed to adjustthe tensionof spring 94. Through the action of spring 94 on rod 9| and accordingly on arm 90, the bell crank lever 86 is urged in a clockwise direction looking in the direction from which Figure 1 is viewed. Connected to the other arm 96 of the bell crank lever 86 is a link 91 which is designed iso to be actuated by a motor so as'A tomove 'cell crank lever 83 in a counter-clockwise direction against the action of spring 94. It will be noted that lever .15 is not directly acted on by the spring 94 or the motor. The only force applied to the levez 15 is that necessary to counteract the weight of the valve. The relatively large moment caused by the opposing actions of spring 94 and the motor is entirely applied to lever 86. The result is that the relatively 'slender shaft 41 upon which lever 15 is mounted is subjected only to a comparatively small side thrust, the greater part of the side thrust being applied to the large bearing member 89.

Link 91 is secured at its upper end to a lever member 99 which is provided with a shoulder adapted to be engaged by a pin |0| of a crank arm member |02 which is driven bythe motor. The structure of members 99 and |02 and the operation thereof will be explained in greater detail ina subsequent paragraph.

Referring to Figure 4, I have shown the motor" mechanism of my valve with a casing |05 therefor shown in section along the line d-d of Figure l. Refen'inglto Figure 4, the motor proper is designated by the'reference numeral it. The particular structural details of this motor are of no importance as far as the present invention is concerned although the motor is provided with two iield windings of different size, as is common .in the motor art, with certain types of motors and as will be explained in greater detail in subsequent paragraphs. The motor is provided with a motor shaft and has secured at the outer end a pinion |0`| which drives through a suitable reduction gearing |08, a shaft |09. The gear at the low speed end of reduction gearing |08 is desig nated by the reference numeral H0. The reduction gearing is designed to provide a very large reduction in speed between its highspeed and low speed ends. This is for the purpose of causing the valve to be moved -slowly from closed to open position. This is a highly important feature where the valve controls the ow of fuel to a very large burner. If the lfuel is not admitted gradually. there is danger of a large amount of fuel being admitti to the burner, before the burner is completely ignited, often causing an explosion.

Three spaced upstanding bracket members ||2, and ||3 are provided for mounting the motor |05, the reduction gear |08 and the shaft |09, as is more or less apparent from the drawings. Bracket member is bifurcated at its upper end to vprovide two spaced poritons H5 and AH6. Portion H6 has secured thereto a bearing sleeve |0. Similar bearing sleeves ||9 are secured in bracket members H2 andA H3. The sleeves ||8 and H9 serve torotatably support shaft |99.

The uppermost portions of bracket and '||2 are bent at right angles and serve to support a plate of insulating material |23 which is shown most clearly in Figurei. Mounted upon insulating plate |23 are `a plurality of switch blades |26, |25 and |26. As shown in Figure 6, switch blade |25 is secured at one end to the insulating plate |23 and is provided at its other ,end with. av contact member |21 which is adapted to engage with a contact-member its rigidly mounted upon insulating plate |23. At its intermediate portion, switch blade |25 is bent downv wardly to provide a cam follower |29 which cooperates with a cam |30. Cam |30 is nonrotatably secured to shaft |09. Cam |30 is provided with an arcuate recessed portion |3| which is suiiieiently recessedso that when the cam fol-v lower |29 is in engagennt with this portion. contacts |21 and |28 are in engagement. It will readily be seen that upon 'a rotation of cam |30 in the direction of the arrow in Figure 6, which direction is the direction in which the cam moves during valve opening movement, contacts |21,

and |28 will rst be separated andthen moved -into engagement for a portion of the movement of cam A|30 and then moved out' of engagement. Upon a reverse movement of cam |30, the same action will takeplace. The function of switch blade |25 and its associated contacts |21 and |20 is to cause a successive energization and deenergization of the lifting coil of the motor during valve opening movement as will be explained l in more detail in subsequent paragraphs.

Referring to Figures 5 and 7 and more particularly to the latter, it will benoted that switch blade |24 is secured at one end to insulating plate |23 and is provided at the other end with a contact |34 ywhichcis adapted to engage with a xed contact |35 on the insulating plate |23. Similarly, switchl member |24 is also provided withv a depressed portion' |36 which serves as a' cam follower and cooperates with a cam member |31. fCam member |31 is provided with square shoulder portions |38 and |39 which engage with the sides of the opening in insulating plate |23 andi serve to linut the movement of cam |31 in opposite directions. Referring again to Figure 4, it willbe noted that earn.` member |31 is located adjacent a collar |20 which is rigidly secured to shaft |09. Located between the cam |31 and the collar 20 is a disk |60 of material having a comparatively high coeilicient of friction. A spring |2| is located onl shaft |09 and serves to urge cam |31 against the friction disk |40'.v Cam |31 is not rigidly secured to shaft |09 and is restrained from free rotation thereon only by being -urged against friction disk |40 by spring |2|.'

portion |4| of the cam, whereupon the shoulder4 |39 will engage the left wall of the opening in insulating plate |23 and prevent further move-l ment of the cam. Continued rotation of the shaft |09 after this occurs merely results in cam |31 slipping on the shaft |819. As soon as shaft W9 is rotated "in `the vopposite direction, cam follower |3E'will move back up onto the raised portion adjacent the depression 4| and the parts will assume the position shown in Figure 7. Continued rotation of the shaft after this occurs again results merely in the cam slipping on the shaft. It will Athus be seen that the operation of switch blade ||3| and cam |31 is to cause an immediate lclosing of contacts |34 and |35 upon rotation of the shaft in one direction and in immediate separation of these contacts upon rotation of the shaft in the other direction regardless ofthe point at which such reverse rotation of shaft begins.

Secured at the outer end of shaft |09 is a sleeve member M5. This sleeve member |45-issecured in any desired manner, but as shown more particularly in Figure 9, the shaft |09 is provided with a square end over which sleeve member |45 extends. A screw |41 serves to secure the sleeve to the shaft |09. Nonrotatably secured at Athe outer end of sleeve is crank disk |02 and" weight rotatably secured between crank disk |02 and shoulder portion |48 on sleeve |45 is lever 99. Referring again to Figure 1, it will be noted that member |02 is provided with a pin |0I, which, upon rotation of crank disk |02 in a counterclockwise direction, is adapted to engage with the shoulder portion |00 of lever 99'. By reason of this construction, a one-way connection between the motor andthe valve is obtained, the importance of which will be more apparent from subsequent paragraphs.

At the end of shaft |09 opposite to that on which sleeve is secured, a pair of cams |52 and |53 are non-rotatably secured as shown in Figure 2. Cam member |52 is designed to actuate a damper arm |54 and cam |53 to actuate a ilare pilot valve |55. Damper arm |54 is pivotally secured to the motor housing |05 by means of a suitable member |50. On one side of the pivot point |50, the damper arm is provided with a weight |5| and on the other side thereof, it is provided with a follower pin |62 which is adapted to move along the cam surface of cam |52. It

will be readily seen that upon rotation of -shaft |09 in the vdirection of the arrow of Figure 2, the cam follower pin |62 rides up on the toe portion |63 of cam |52 causing the left end of lever |54 to move downwardly against the action of |5|. Damper arm |54 is employed to actuate a secondary air damper as will be more apparent vfrom a subsequent description of the operation of the valve.

The iiare pilot valve |55 comprises a housing |56 which is secured through any suitable fastening means |49 to the side of the valve cap 50. The valve body |56 is provided with a vertically extending passage |51 which has extending across it acacent its mid point an apertured partition.

|58. This partition |58 serves to provide a valve seat upon which a valve head |59 is adapted. to seat. Secured in the lower end of the valve body |56 is-a plug member |60 which has a recessed portion in which is mounted a spring 6|. Spring |8| bears against the valve head |59 so vas to urge it to closed position. 'I'hreadedly secured in the upper end of the pilot valve housing |56 is a sleeve member |64 which is provided at its lowermost portion with an -annular extension This extension serves a joint function of guiding the valve stem |66 attached to valve head |59 and of engaging valve head |59 to limit lits closing movement. It will be seen that by screwing sleeve |64 in or out, the closing movement of the valve may be limited to any desired extent. A lock nut |61 is provided for the purpose of locking a sleeve |64 in any adjusted position. Secured in the upper end of sleeve |64 is an annular guide'member |68 which serves to further guide the movement of valve stem |66. Located'within sleeve |64 is a. suitable packing material |10 which is urged in sealing engagement with shaft y|66 throughv a spring |1| which bears at one end against guide member |68. 'Ihe pilot valve housing is provided with a transversely extending passage |12 which communicates with a lower portion of chamber |51 and is in further communication with a passage |13 extending through the valve housing cap 50. Gas is permitted to enter the lower portion of ,chamber |51 through passages |13 and |12 from the interior of the main valve housing. A pipe |14 communicates with the upper portion of chamber |51 on the opposite side of valve |59.

v of the valve by the motor.

of the motor housing |05. At its lower end, member |15 is provided with a conical portion |11 which is adapted to engage the upper end of valve stem |66. At its upper end, member |15 is provided with a roller |18 which functions as a cam follower and bears upon the cam surface of cam |53. It will be noted that cam |53 is provided with a toe portion |19 of limited extent so that upon continued rotation of cam |53 in the direction of the arrow of Figure 2, the cam will be effective to move member |15 to depress valve stem |66 for a short period to time and then to permit the same to move upwardly` again by.

reason of the biasing action of spring |6|. Since this valve is used to control the flow of gasto the pilot burner, this action of the cam will be effective to cause the normal flow of gas to the pilot, as determined by the extent to which valve |59 is held away from its seat by annular extension |65, to be momentarily increased so as to are the pilot outwardly. Cam |53 is so lo- Y cated with relation to the opening movement of able crank orV key member to squared shaft |82.

By the application of such a key or crank member to shaft |82, the gear train may be manually rotated in the event of power failure. lThis causes the valve to be manually operated in a manner to be more fully described later.

Referring lto Figures 11 and 12, there is shownV a means for latching the valve in open position when manually opened and for insuring that the valve is returned to the control of the motor upon restoration of power. In Figure 11,- the gear train is shown in an end view. Attached to the end gearl |0 of the low speed end of the gear train |08 is a pin |84. This pin |84 serves a double function during the normal operation Pin |84 serves to limit the opening movement of the motor by engaging a stop pin |85 which is secured in bracket ||3. When the valve is manually operated, pin |84 cooperates with a latching member 86 to hold the valve in open position. Latching member |86 is pivotally mounted to an upstanding bracket |81, as shown more clearly in Figure 12.

This bracket |81 is secured to bracket ||3 as indicated in Figures 4, 11 and 12. Latching member |86.is provided with an upstanding shoulder portion |88 and bracket |81 is similarly provided with such a shoulder portion |89. A coil spring |90 is located upon a pin |9| which serves to pivotally connect latching member |86 to bracket |81 and the ends of the spring bear against the respective shoulder members |88 and |89 serving to urge member |86` into the position shown in Figure 11. A pin |92 is located on bracket I3 and limits the outward movement of latching member |86 by engaging with ane'xtension |93. This extension |93 is curved so as to be able to securely engage with pin |84. When the valve is manually raised and it is desired to latch the valve in open position, latching member |86 is moved inwardly by pulling down upon a handle portion |95 thereof, so asto bring the curved surface of extension |93 into the path of the return movement of pin IBI. This position,4

looking in the'direction opposite to that from which Figure l1 is viewed, is shown in lFigure 12. It will be seen that the latching member |86 through the engagement of extension |93 with pin |84 is effective to prevent the return rotation of gear H6. Moreover, by reason of the curved surface of extension |93 engaging with the curved surface ofv pin |86, latching member |86 lis held in its locked position when released due to the fact that pin- |88 is urged against the curved surface of extension |93 and thus locks latch |86 in the position shown. l

The operation of moving the latch inwardly has a further eiect which will now be described. Referring to Figures 4, 5 vand 12; it will be noted that latching member |86 is provided with a projecting stud |9ll of insulating material which is adapted to be moved downwardly when latching member |26 is moved into latching position. YThe spring blade |26, which was previously referredr to as mounted upon plate |23, has one end located in the path of movement of stud ist.

This spring blade |26 has a contact |99 secured.

theretowhich contact is adapted to be moved into engagement with a stationary contact'md upon base |23. As will be apparent from Figure d, downward-movement of insulating stud itl, such'as occurs upon a moving of latching member |36 into latching position, causes spring blade |26 to be moved downwardly and toeiiect the engagement of contacts I9@ and 26|?. The engagement of these contacts will result in the closing of a circuit to the motor independent oi the'normal control means as will be apparent from the description of the operation in a subsequent paragraph.

In Figure 13, I have disclosed a schematic view of a burner system employing my improved valve. In this gure, the valve is shown in a highly schematic form for the purpose of more clearly understanding the action thereof. Inasmuch as the elements of the valve are designated by the same reference numerals as employed in connection with the previous description of the valve, it is unnecessary to specifically describe these elements again in connection with this va ve.

Referring to said iigure, a main-gas burner dit is shown as located within any suitable furnace 2||. Gas is supplied to the main burner 2|@ through a pipe 2|2 which communicates with gas supply pipe 2id, the communication of which is controlled by the valve of the present invention. A pilot burner is designated by the refervence numeral 2id and Iis supplied with fuel through pipes 2|5 and 2|6, the communication of which pipes is controlled by the dare pilot valve |55. -Pipe 2|@ leads to 'the gas supply pipe 2|?, and is connected thereto independently oi the main valve it. This pipe corresponds'to the passage in the valve mechanism provided by the interior of valve housing mand by passage llt.

The admission of secondary air to the gas burner is controlled by a secondary air damper 2id which is pivoted to the furnace casing at 2id and is adapted to open downwardly by the action of vgravity when permitted. A exi'ble connecting means, such as a chain, is indicated by the reference numeral 22@ and is employed to connect the damper Zit Withdamper arm ld.

As previously explained, the motor it@ is conventional with the exception that it is provided with two field windings, one ofsubstantially greater size than the other. Referring to vFigure 13, the rotor of the motor is designated by the reference numeral 225. Associated with said rotor is a low torque eld winding 226 and a high torque eld winding 221. winding 226 serves as a holding coil and the high torque iield winding 221 as a lifting coil.

Power is supplied for operation of this system through a step-down transformer 230. 'I'his transformer comprises a line voltage primary 23| which is connected to line wires 232 and 233 leading to a suitable source of power (not shown).

The low torque eld The step-down transformer comprises in addition a core 234 and a low voltage secondary 236.

A control switch is generally designated bythe referencel numeral 266. This control switch may take any desired form but in the present instance is shown as a thermostatic switch comprising a bimetailic element 26| to which is attached a contact arm 242. Secured to the contact arm 242 are contacts 24d andddd which are adaptedto be moved into engagement with xed contacts 236 and 2de, respectively. As will be noted from the drawings, contacts 2d@ and 245 are more widely spaced than contacts 2te and' 24d. The bimetalv lic element 2M is so arranged with respect to the contact arm 262 that upon a decrease in temperature the contact arm is moved in the direction of .the stationary contacts 265 and 266. When such a drop in temperature occurs, contacts ad@ and 2d@ will rst be moved into engagement by reason of their closer spacing and upon aiurther drop in` perature, contacts 26d an l 2de will'be moved into engagement.

' Operation position.

Assuming now that the temperature falls below the value for which the thermostatic switch 266 is maintained, engagement will rst be effected of contacts 2M and 246. The engagement of these contacts lwill not, however, cause the estabiishment of any energizingcircuit. If the drop in temperature continuesl a predetermined amount, engagement of contacts 243 and 2d@ will also be enacted. Upon this occurring, the

following 'energizing circuit for-the low torque ield winding or holding coilf226-is established; from the righthand terminal of secondary 235 through conductor 25d, contacts 286 and 2M, contact arm 262, contacts 243 and 246, conductors 25| and 262, holding coil 226, conductor 253, and

conductor 256 to the other terminal of secondary 23e. s will cause the energization of ield winding 226 which though not exerting sumcient torque to raise the valve does exert sumcient torque to rotate the motor up till' the time that pin lili moves into engagement with shoulder i6@ of lever 99. Due to vthe'actftlnatt during valve closing movement, the motor and gear train have considerable momentum and continue to run backwards after the valve has reached its seat, crank disk m2 will be ina position such that pin' lili is considerably spaced from shoulder "it, thus permitting a substantial amount of rotation of shaft |06 by the motor |06 before 'l5 engagement of pin |0| and shoulder |00I is effected.

The initial rotation of shaft |09 is effective to permit the cam follower |36 of the switch arm |24 to move downwardly into the recessedportion |4| of cam |31 so as to effect engagement of contacts |34 and |35. When this takes place, the following holding circuit is established for field winding 226: from the right hand terminal of secondary 235 through conductor 250, contacts 246 and 244, contact arm 242, bimetallic element 24|, conductor 255, contacts |35 and |34, switch arm |24, conductor 252, field winding 226 and conductors 253 and 254 to the other terminal of secondary 235. It will be noted thatv the holding circuit just traced is independent of contacts 243 and 245. Thus if the temperature momentarily rises slightly so as to cause disengagement of contacts 243 and 245 without causing disengagement of contacts 244 and 246, the eld winding will remain energized. In this manner I guard against the periodic energization and deenergization of the eld winding such as would occur with a slight but rapid iiuctuation in temperature.

Immediately after the engagement of contacts |34 and |35, the cam follower |29 ofv switch blade |25 moves.down onto the recessed portion |3| of the cam surface of cam |3i0 permitting the engagement of contacts |21 and .|28. As soon as this takes place the following circuit is established for the lifting coil 221: from the right hand terminal of secondary 235 through conductor 250, contacts 246 and 244, contact arm 242, bimetallic element 24|, conductor 255, contacts |35 and |34, switcharm |24,`conductorsv 251, 258 and 259, switch arm |25, contacts |21 and |28, conductor 260, lifting coil 221, conductor 26|, and conductor-254 to the other terminal of secondary 235,. It will be noted that the closing of contacts |21 and |28 in effect connects eld Winding 221 in parallel with eld winding 226 between the junction of conductors 251 and 258 and the junction of conductors 26| and 253. It will be noted that the lifting coil 221 was not connected 'into the circuit until after the establishment of the holding circuit by reason of the engagement of contacts |34 and |35. 'Ihis is highly desirable due to the fact that until the holding circuit is established, the energization of the field windings is somewhat uncertain due to the possibility of immediate separation of thermostat contacts 243 and 245. Since the eld Winding 221takes considerable more current than eld Winding 236, it is desirable that winding 221 be not connected into the circuit until the holding circuit has been established with the result that the circuit will remain established.'

With both the lifting and holding`coils 221 and 226 energized, it is possible for the valve |0 to be'. opened. 'The motor is now effective to rotate shaft |09 causing the pin |0| 'to move into engagement with thershoulder |00 causing lever 99 to move in the direction of the arrow of Figure 1. .This causes 'an upward movement to be imparted to link 91 which in turn causes a counter-clockwise rotation of bell cra-nk 8 6 against the action of spring 94. v'Il'iis counterclockwise rotation of bell crank 86 is imparted to lever 15 which in turn causes a similar rotation of shaft 41. As previously explained, this counter-clockwise rotation of shaft 41 is effective to lift the valve stem 34 causing the valve disk 23 to 'rst be lifted oft of its seat on large valve disk |4 relieving the pressure on the large disk and then to lift the large valve disk |4 opening gear trainl employed.

. burner.

the valve 0. This permits a flow of gas to the main burner,2|0.

It will be noted in Figure l that the angle between lever 99 and link 91 in the position assumed when the valve is closed is slightly greater than 90. Similarly, the angle between link 91 and arm 96 of lever 86 is slightly less than 90. likewise, the angle 'between arm 90 of lever 86 and rod 9| is slightly greater than 90. The result is that after an extremely small amount of movement of'4 these elements in valve opening direction, they are all disposed perpendicularly to each other and the spring is operating against the motor through a maximum moment arm. As the valve moves farther toppen position, this moment arm decreases. This decrease in moment arm is accompanied by an increase in the force exerted by the spring 94 as it becomes4 ing valve wherein the spring must be quite powerful in order to rotate the rather long If no arrangement is provided for maintaining the moment exerted by the spring comparatively constant, the motor must be of an excessively large size to overcome -both the friction of the gear train and the force Aof the spring during the final portion of the opening movement of the valve.

Before the main valve is opened and even before pin |0| has engaged shoulder |00, the toe portion |19 4of cam |53 has engaged the end of member |15 depressing thevalve head |59 of pilot valve |55, thus increasing the flow of gas to the pilot burner 2|4. The toe portion |19 of cam |53 extends sufficiently far to maintain the flame of the pilot burner 2|4 extended until the main valve i0' has opened appreciably. I'he result is that while gas is being first admitted to the main burner 2|0, the pilot flame is extended so as to facilitate the ignition of the main Before the valve I0' has reached `full open position, however, member |15 has ridden oifof the other side of the toe portion |19 so as to again permit valve |59 to assumea position of minimum flow. While in the previous decription, the sleeve |64 of flare pilot valve |55 is so adjusted as to constantly maintain a minimum flow of gas through the iiare pilot valve, it is wholly possible, ifl some means is provided for igniting the pilot, to have this adjusted so that the flare pilot valve is entirely closed and is opened upon the valve being opened. While I have shown for purpose of illustration the valve as employed in connection with the type of system wherein the pilotis constantly burning when' the main valve is closed and is flared when it is desired to ignite the main burner, it is to be understood that my structure isnot limited to this use in lany manner whatsoever and that it is just as adaptable for use in the type of system wherein the pilot is intermittently operated.

aieavea opening secondary air damper, my damper actuating mechanism is adaptable for use with a secondary air damper which opens outwardly. All that is necessary to do this is to reverse the connections of chain 220 and weight |5| to the damper arm,the position of weight |5| beingadjusted in accordance with theweight of the secondary air damper.

Referring again to the opening of the main valve, the continued rotation of shaft |09 such as occurs during this opening process causes cam |30 to assume a position wherein cam`fol1ower |29 is again moved, out of the recessed portion |3| so as to again cause separation of contacts |21 and |28. When this occurs, the previously traced circuit to lifting coil 221 is interrupted so that only the holding coil 226 remains energized. Whilev the holding coil 226 exerts insuflici'ent torque to lift the valve, it is sufcient, due to the friction of the gear train, to hold the valve in open position. `As previously explained, the

opening motion of .the gear train is stopped by reason of pin |84 engaging stop pin |85.

engagement with pin |85 and to thus hold the valve open. Due to the fact that the vcurrent consumption of the holding coil is relatively small, the heating caused by the continued energized position by a spring since it is imperative that the bearings do not stick', as will often result if they are heated excessively by heat given oi! by the motor.

As soon as the temperaturey to which thermostat 240 4is responsive has risen above the value for which it is set so as to cause disengagement of contacts 244 and .246, all the circuits previously traced will be immediately interrupted so that the motor is completely deenergized.` As soon as this occurs, spring 94 acting through bell crank lever 06, is eiective to return the valve to closed position. As the valve reaches closed position, the are pilot valve |55 will again be moved open to cause aflaring of the pilot name so as to insure that the diminished quantity of gas issuing from burner 2|0 is completely burned. At the Sametime, cams |30 and |31 will be effective to assume the position shown in Figure 13 causing separation of not only switch contacts |21 and |28 but also contacts |34 and |35. .Upon the main valve reaching its seat, the motor and gear train have acquired sufficient momentum so that they continue to rotate. This continued rotation is possible by reason of the one-way connection afforded by pin |0| and shoulder |00 of lever 99. By' reason of this possibility of the continued rotation of motor and gear train, rebounding of the valve from its seat is prevented. A

If it should happen that there is a power failure and it is desired to open the valve, the same may be manually opened as previously explained. This may be' done by inserting a crank such as crank 264 onto the square end |82 of shaft 18| and rotating the entire gear train, thus opening the valve. When the valve reaches substantially open position, latching member |86 is moved inwardly by pulling down on handle-|95, as previouslv explained, causing the curved shoulder of extension |93 to be moved into the return path of pin |04. The crank is then released allowing The holding coil is now effective to hold pin |84 in pin ece tc seat against this curved shoulder which retains the latch in its inner position.

As previously explained, the inward movement of latch |86 eiects the engagement of contacts |99 and 200. "I'he engagement of these contacts is effective to cause energization yof the eld Winding 226 through the following circuit as soon as power is restored: from the right hand terminal of secondary 235, through conductor 262,

switch blade |26, contacts |99 and 200, conductors 250, 25| and 252, eld winding 226 and conductors 253 and 254i to the other terminal of sec- .ondary 235. Because of the fact that the position of the curved shoulder of extension |93 permits suicient return movement of gear ||0 before pin I|86 engages therewith, the cam follower |29 of switch arm |25 will be in the recessed portion |3| of camA |30 so as to eect engagement between contacts '|27' and |20. Accordingly,

upon restoration of power, the followingcircuit rotate the shaft |09 against the action of spring St so as to cause a further opening of the valve. This additional rotation of shaft |09 causes pinv it@ to` be moved away from engagement with the curved shoulder of extension |93 of latch |06, thus permitting latch |86 to be released and returned by reason of the biasing action'of spring |90 to the position shown in Figure 11.

The movement of latch |86 hack to its normal position causes switch arm |26 to eiect a disengagement of contacts |99 and 209; If the thermostat 240 is now in a closed position calling for the valve to be opened, the motor will remain energized and move vthe valve to full open position. If on the other hand, the thermostat contacts are separatedindicat-ng that the temperature is such as not to require the further maintenance of the valve in open position. the separation of contacts |99 and 200 will cause the motor to be deenergized so that the valve is returned to closed position. In this manner, I assure that if the valve is manually opened and latched in open position. there is. no danger of the same remaining out of control of the thermostat-when power is restored. This is highly desirable inasmuch as the latching of the valve in open position and the inadvertently latching of the same in open position after restoration of power will defeat one of the very objects of the automaticl control, that is, greater safety. A

InFigures 14 and 15, thereis disclosed a modication wherein means are provided for adjusting the movementof the valve without changing the action of any of the rest of the apparatus. In

F'gure 14. the elements which diier from those Y in the preferred form are shown in heavier lines than the rest of the structure. It will be noted that in lieu of the one vertically extending link v 91 in the preferred species there are now `two ver- Th'ere is no connection between levers 215 and 296 as there is between the corresponding elements of the preferred species, and the actuation of lever 215, and consequently of the valve, is effected directly through link 298 rather than through the bell crank 296.

Means are provided for adjusting the connection of link 298 with lever 299. This adjustment is such that the position of lever 299 with respect to the pivot point is varied so as to decrease or increase the throw of the valve without affecting in any way the movement of lever 299- or of bell crank/296. Referring to Figure 15, it will be noted that lever 299 is substantially different in construction fromlever 99 of the preferred species. Lever 299 comprises two strips 304 and 305, the former of which is pivotally mounted to a shaft 309- driven by the motor, which shaft corresponds to shaft |09 in the preferred species. These two strip members 304 and 305 are secured together at one end by means of a bolt 306 and at the other end by a bolt 301. sleeve 308 surrounds the bolt 301 to prevent members 304 and 305 being drawn so closely together as to grip the lever 291 which is pivotally mounted on the sleeve 308. Located in the outermost strip member 305 is an arcuate slot 3I0 whose center of curvature coincides with the pointof connection of link 298 with lever 215 when these two members are in closed position. A pin 3|| extends'through this slot. This pin is provided with' a portion 3|2 of substantial diameter and a reduced shank portion 3|3. A shoulder is provided at the junction of these two portions, which shoulder engages one side of member 305 of lever 299. A nut 3M is threaded on the shank portion Iand serves to clamp pin 3| I in position, serving to clamp the shoulder formed by the junction of portions 3|2 and 3I3 rmly against member 305 and serving to hold the same in any position in which it has been set.

The link 298 comprises a pair of eye bolts 3|5 and 3|6 adjustably connected throughv a turnbuckle 3|1 of any desired construction. The eye of eye bolt 3|5 surrounds the portion 312 of pin 3H so as to form a pivotal connection between link 298 and lever 299. Due to the fact that the portion 3|2 of pin 3|| has a length which is greater than the width of the eye portion of eye bolt 3|5, the eye bolt 3|5 remains freely pivotal with respect to pin 3|| regardless of how tightly nut 3|4 is clamped. The other eye bolt 3|6 of link 298 is pivotally connected to lever 215.

It will thus be seen that means are provided for adjusting the radial position of the connection of link 298 with lever 299 and hence varying the throw of the valve. An important feature of the construction employed by me is that it is possible to adjust the movement of the valve for a given movement of the motor without in anv way affecting the tensioning of the biasing means necessary to effect such movement. If in the preferred species the link 91 were merely'made adjustably connectable with lever 99, the movement of the `valve for a given movement of the motor could be varied but in so doing the tensioning of the spring 94 that would be necessary to effect sucn movement would likewise be varied. This is highly undesirable inasmuch as in some cases the spring would be very strongly compressed and in other cases only slightly compressed. If the apparatus were adjusted to function satisfactorily for one tensioning of the spring, it would not function satisfactorily for a diiferent tensioning In the latter case, a"

present structure.

of the spring. This is due to the fact that the spring must be carefully/'adjusted so as to just have suii'icient tension to return the valve with the proper amount of force without having so much tension as to prevent satisfactory operation of the valve by the motor. By the provision of the arrangement shown in Figures 14 and 15, it is possible to adjust the movement of the valve without in any way affecting the tensioning of the spring necessary to effect such movement. This is accomplished by reason of the fact that the spring acts on bell crank lever 296 and this lever moves through 'the same arc of movement regardless of the amount of movement imparted to the valve.

Another advantage of this construction is that due to the fact that the center of curvature of slot 3I0 is at the junction of link 2|6 and lever 215 when these members are lin valve closed position, the throw of the valve can be varied vwithout affecting the valve closed position of the operating mechanism. In certain prior constructions of a similar type, it was4 necessary to readjust the mechanism each time the throw of the valve was varied, to permit lthe valve to close properly.

While the feature of the operation of Figures 14 and 15 is applicable,v to any type of motorized valve or for that matter" to various'types of mechanisms broadly, it is of particular advantagev Where the motor is of the modulating type wherein the valve may be moved'to and stalled in any midposition. Such motors are well known to the art and as an example of one such motor which would be suitable for use in vconnection with a valve of this type, is the motor mechanism shown in the patent to Lewis L. Cunningham No. 2,029,465 of February 4, 1936. In the structure of this patent, the pin 51 and the gear .55 would correspond in function to the pin 30| and the lever 302 of the structure suitable for use with this valve is the patent to Willis H. Gille No. 2,032,658 of March 3, 1936. In this patent the shaft 2| would correspond to the shaft 309, the arm 22 to the lever 302 of the present structure and spring |8 to the biasing spring of the instant structure. However, while the invention finds particular utility in connection with a modulating motor such as is disclosed in the two patents just mentioned, it is of a broad general applicability, as previously stated, and is of utility in connection with a motor such as is disclosed in the preferred species where it is desirable to adjust the throw of the valve.

In Figures 16 to 18, I have disclosed a modication wherein the are pilot valve is actuated from the bell crank lever and wherein the pilot valve remainsfully open during the entire time that the burner is in operation. Referring to Figures 16 and 1'?,v it will be noted that a rearwardly extending arm 330 is secured to a bell crank lever 33|. This rearwardly extending arm 330 ls preferably fastened by screwsor other suitable fastening means 332 to a hub portion 333 of the bell crank lever 33|, which hub portion corresponds to the hub portion 88 of bell crank lever 86 in my preferred species. The arm 330 is provided with a horizontally extending'flnger 335 which is designed to cooperate with the nare pilot valve 336 to actuate the same.

Referring to Figure 18 wherein the pilot valve 336 is shown in cross section, it will be noted that the pilot valve comprises a housing including a main body portion 331 into which is threaded a Another example of a motorA valve guide member 338. A valve seat 339 is in 75 communication with a pipe 342 and is adapted to have a valve head 34| seated thereon. When the valve is moved from its seat, communication is permitted between pipe 342 and a second pipe 3&3, one of which is intended to be led to the gas supply and the other of which is intended to be led uto the pilot burner to supply gas to the same. A valve stem 344 is connected to the valve head 34H at one end and at its other end is secured to a block 345. The guide member 338 is provided with a threaded recessed extension Mt, onto which is threaded a sleeve 341. The sleeve ttl serves to limit movement of block 345 and consequently of valve 34| in valve closing direction. By adjusting the sleeve 341 the amount which the valve is held open in its minimum now position maybe adjusted. A lock nut 348 is provided for securing sleeve 34'! in any adjusted position. A spring Mt is located in the recessed portion of extension 34S and serves a dual function of urging block 385 outwardly and hence biasing the pilot valve to an open position and also of compressing packing 35i serving to eectively seal the valve stem tot.

Bearing against the lower end of block tot is a pin 353 which has a conical head 35d extending into a conical recess tot of block 365. 'lhe pin 353 entends through the horizontally extending portion 335 of the arm 33t. A spring @5t is located between the conical head tt and the portion 835 of arm 233@ and serves to urge the conical head &3 away from member 335, providing e, strain release connection between member 385 and block 355. A nut @to is threaded onto the lower end oi pin 353 and serves to limit the movement of headll away from member 335. It will hereadily seen that upon a counter-clockwise movement ci hell crank levertlhthe portion 335 Aoi arm 353@ will he moved downwardly. The downward movement of this portion will cause the downward movement of pin 35g) permitting the biasing spring@ 3639 to move hlochj @llt and consequently valve head fidi down so as to open the pilot valve 35d. Referring again to Figure 16, it will Bevnoted that the lever 365 which is connected to hell crank lever Bill is slotted at tot and that the pin et@ which serves to connect the lever tot with hell crank lever 533i ennds: through this elongated slot 356 and is free tomove up and down thereon. The provision of this pin and slot connechon resuits in there heing'lt motion between the hell crank lever 233i and the lever title. Thin upon a valve opening movement, hell crank lever liti will move a slight distance in a counter-clockwise direction before causing any movement whom ci' lever litt and consequmtlyof the main valve. This movement of hell crank lever 336 before the lost motion between the lever. tti and lever. tot le taken up is summent to move portion' 335 of arm 3l@ downwardly sumiently to cause the dare mio/t valve 233@ to be fully opened. In this'manner, the nare pilotlyaiveis moved to fun coen position before the gas is admitted to the main hurner as in the preferred species.

While I have described my valve as employed A ln connection with the supply of fuel to a burner control it is to be understood that certain features thereof are broadly applicable 'to any iiuid ilow controlling element and in some cases even to any motor actuated element. Moreover, there are certain features of the burner control :systemy in-which my valve is incorporated which are oi' broad general utility regardless ofv whether the valve happens to be a motorized valve `ofthe'type shown in the drawings. VGenerally speaking, I have shown certain specific embodiments of my invention. It is to be understood that these are for purposes of illustration and that my invention is to be limited only by the scope of the appended claims.

I claim as my invention:

1. In combination, a valve, means biasing said valve to one position, a motor for moving said valve to a second position, a lost motion connection between said motor and said valve whereby movement of said motor does not cause immediate movement of said valve, said motor comprising a rotor and a plurality of eld windings, one of which is adapted to exert a relatively small torque on said rotor when energized and the other of which ,is adapted to exert a relatively large torque when energized, a source of electrical energy, a control switch having a pair of contacts which tend to be insecurely engaged and operative upon engagement of said contacts to cause energization of said eld winding of relatively small torque to cause an initial movement' of said motor, and switching means operative upon such movement to nrst establish a circuit independyent of said pair of contacts between said source oi energy and said all torque eld winding and to then include said large torqueeld winding in said circuit in parallel with said small torque held winding, said operation o said switchlng means hnng completed heiore the lost motion between said motor and said valve has been completely taken up.

2. In combination, condition changing means, e. device controlling the condition changing mns, a motor-'tor operating said device, a lost motion connection between said motor and said device so that initial movement 'of said motor does not cause' movement ci said device; said motor comprising a rotor and a plurality of held windings, one oi which is adapted to exert a relatively small torque on said rotor when energized and the other of which is adapted to exert a relatively large torque when energized, a source oi electrical energy, a condition responsive switch having two sets oi contacts sequentially engage-- able and disengagcalole upon changes in the controlling condition adapted upon closure oi both sets of contacts to cause energimtion oi the held winding of relatively small torque to eect an initial movement of said motor, and switching mwns operative upon such movement to establish a circuit independent oi the idrst to be disengaged of said contacts mtween said source of energy and cmd large torque held winding.

3. In combination, condition changing means, a device controlling the condition changing means, a motor for operating said device, a lost motion connection `between said motor and said device so that initial movement of said motor does not cause movement of said device, said motor comprising a rotor and a plurality of eld windings, one `oil which is adapted to exert a relatively mall torolue on said rotor when energized and the other oi which is adapted to exert a relatively large torque when energized, a source of electrical energy, a condition responsive switch having two sets oi contacts sequentially engageable and disengageable upon changes in the controlling condition adapted upon closure of both sets of contacts to cause energization of the eld winding of relatively small torque to eiIect an lnitialmovement of said motor, and

switching means operative upon such movement to ilrst establish a circuit independent of the x'st to be disengaged of said contacts between said source of energy and said small torque iield winding and to then include in said circuit said large torque field winding in parallel with said small `torque field winding.

' 4.'In combination, a fluid flow vcontrolling member, a tension spring biasing said member to one iiow controlling position, a rotary electical motor, connecting means between said motor and said iiuid flow controlling member such that operation of said motor .moves said member to a second flow controlling position against the action of said spring, means for varying the movement of said member for a given movement of said motor without changing the amount of tensioning of said spring necessary to accomplish said movement of said member.

5. In combination, a uid flow controlling member, a rotary electrical motor, connecting means between said motor and said member effective upon operation of said motor to move said member from a first fluid controlling position to a second fiuid controlling position, means including a tension spring acting on an element of said connecting means to constantly urge said member to said rst position, andmeans for varying the movement of said member for a given movement of said motor without varying the amount of tensioning of the spring necessary to accomplish said movement of said member.

6. In combination a fluid now controlling member, a tension spring, a motor, a support, a shaft rotatably mounted in said support, operative connections between said shaft and said member to be actuated whereby rotation of said shaft causes actuation of said member, a first lever driven by said motor, a second lever, a connection between said first lever and said second lever and between said second lever and said spring whereby said spring acts through said second lever to urge said rst lever in a direction opposite to that 'in which it is driven by said motor, and a connection between said rst leverv and said shaft whereby the movement of said first lever is transmitted to said fluid now controlling member, said connection being adjustable to vary the amount of movement of said flow controlling member for the same movement of said first lever.

'7. In a slow opening valve mechanism, a relatively high speed motor, a reduction gear train having a large reduction ratio and having the high speed end thereof connected to said motor, a linkage mechanism connecting said valve to the low speed end of said gear train, so that upon energization of said motor, said valve is slowly moved to open position, yieldable means connected to said linkage so as to' oppose the movement thereof in valve opening direction, said yieldable means being of suflicient strength to be operative upon deenergization of the motor to rotate through said linkage said gear train and said motor in the opposite direction to close a valve, v

said'valve, the elements of said linkage being so Y disposed relatively to said spring that the moment arm through which said spring opposes the opening movement of said valve decreases as the valve moves to open position.

8. In a slow opening valve mechanism, a valve, a motor for moving* said valve to open position, a reduction gearing having a large reduction ratio for connecting said motor to said valve, means for biasing said valve to closed position, said biasing means having sufficient force to move said valve to closed position and rotate said gear train and .motor in valve .closing direction upon deamarte' energlaation of said motor, asupport, a shaft rotatably mounted in said support, operative connections between said shaft and said valvev whereby rotation of said shaft causes actuation of said member, a lever which is connected at spaced points to said biasing means and through said reduction gearing to said motor, a bearing for said lever securedto said support concentrically with said shaft and of sumcient size to withstand the side thrust caused by the forces exerted by said biasing means and said motor and a connection between said lever and said shaft whereby movement ,of said lever is imparted to said shaft to cause actuation of said valve.

9. In a slow opening valve mechanism,a valve, a motor for moving said valve to open position, a reduction gearing having a large `reduction ratio for connecting said motor to said valve, means for biasing said valve to closed position, Asaid biasing means having sufficient force to move said valve to closed position and rotate said gear train and motor in valve closing direction upon deenergization of said motor, a support, a shaft rotatably mounted in said support, operative connections between saidshaft and said valve where- ,by rotation of said shaft causes actuation of said member, a bell crank lever one arm of which is connected to said biasing means and the other of which is connected to said motor, a bearing for said lever secured to said support concentrically member whereby operation of said motor moves said member to one flow controlling position, adjusting means whereby the amount of movement of said member for a given movement ofl said motor may be varied, and means independent of the adjustment ofthe adjusting means for at all times exerting a substantially constant tension on said member, for biasing said member in a direction opposite to that in which it is moved by said motor.

11. rn combination, a fluid. now controlling.

member, a rotary electrical motor, connecting means between said motor and said member effective upon operation of said motor to move said member from a first fluid controlling'position to a second fluid controlling position, means for varying the movement of said member for a given movement of said motor, and means, including a tension spring, for at all times exerting a substantially constant tension on said member to urge said member to said first position, whereby the same tension will always be exerted on said valve regardless of the movement imparted thereto by said motor. 'i

l2. In combination,`condition4 changing means,

a device controlling the condition changing' means, amotor for operating said device, a lost motion connection between said motor and said device so that initial movement of said lmotor does not cause movement of said device, said field windings, one of said windings exerting sumcient torque when energized tocause rotation of said rotor before the lost motion is taken up but insufficient torque to cause rotation of the rotor after the lost motion has been taken up,

4motor comprising a rotor and a plurality of aisaiea Y another winding creating suillcient torque so that when both windings are energized, therotor is caused to rotate after the lost motionhas been taken up, a source of electrical energy. a condition responsive switch having two sets of contacts sequentially engageable and disengageable upon changes in the controlling condition operative upon closure of both sets olf contacts to cause energization of said one eld winding, and switching means operative upon movement of the motor under the influence of said one iield winding to establish a circuit, independent of the last of said contacts to be engaged, between said source of energy and said other field winding.

13. In combination, a burner, a main valve in control of the flow of fuel to said burner, a pilot burner, a pilot burner valve, a motor, reduction gearing driven by said motor, lever means connected to said main valve, means biasing said main and pilot valves to closed positions, an operating member connected to said pilot valve, valvef'actuating means driven by said reduction gearing, said means including a crank pin, means connected to said lever means locatedin 'the path of movement of said pin, said means being so congurated and arranged' with respect to said pin that upon engagement by said pin in response to rotation of said gearing by said motor in one direction, said means Awill be moved by said pin in a direction to cause the opening of the main valve and will be retained in valve open position by said pin as long as the motor remains energized, the biasing means for the main valve:

being of suilicient strength that upon deenergization of said motor, said motor will be caused to run in a reverse direction by reason oi' the force imparted to said pin, the momentum of said motor keeping the motor running long enough to carry the pin a substantialdistance from the -means connected to the lever means, whereby upon energization of the motor, there will be considerablelost motion beforethe pin starts to open the main valve, and-means for causing said pilot valve to be opened. by said motor during the period that the lost Vmotion is being taken up.

14. In combination, a burner, a main valve in control of the flowof fuel to said burner, a pilot burner, a pilot burner valve, a motor, reduction gearing driven by said motor, lever means connected to said main valve, means biasing said main and pilot valves toI closed positions, an

operating member connected to said pilot valve,

valve actuating means driven by said reduction gearing,- said means including a crank pin, means connected to said lever means located in/"the path of movement of said pin, said means being said pin that upon engagement by said pim in response to rotation of said gearing by said motor in one direction, said means will be moved by said pin in agdirection to cause opening of the main valve and will be retained in valve open position by said pin as long as the gearing is under the control of said 'motor, the biasing means for the` main valve being of suiiicient strength that said gearing will be caused to run in a reverse direction byy reason of the force imparted to saidpin, when the gearing is no longer under the control of said motor, the momentum of the gearing being suillcient to carry the pin a substantial distance from the means connected to the lever means, whereby upon energization of theA motor, there will be considerable lost motion before the pin starts to open the main valve, and means responsive to the operation of the motor during the time that the lost motion is being taken up for causing said pilot valve to be opened against the action of the biasing means.

CARL e. KaoNMmLER, l

`so congurated and arranged'withrespect to 

